"I write a trivia column for a newspaper called The Austin Chronicle. Someone has asked me the origin of the word daemon as it applies to computing. Best I can tell based on my research, the word was first used by people on your team at Project MAC using the IBM 7094 in 1963. The first daemon (an abbreviation for Disk And Executive MONitor) was a program that automatically made tape backups of the file system. Does this sound about right? Any corrections or additions? Thank you for your time!"

"The words daemon and daimon are Latinized spellings of the Greek Î´Î±Î¯Î¼Ï‰Î½ (daimÃ´n), a reference to the daemons of Ancient Greek religion and mythology, Hellenistic religion and philosophy. Daemons are good or benevolent "supernatural beings between mortals and gods, such as inferior divinities and ghosts of dead heroes" (see Plato's Symposium), and differ from the Judeo-Christian usage of demon, a malignant spirit that can seduce, afflict, or possess humans." http://en.wikipedia.org/wiki/Daemon_(classical_mythology)

So the Xian's might object to the pagan origin of the term. I am sure this is the allusion that the originators of the acronym meant. The were probably literate enough to know Plato's use of the term and were referring to these benevolent behind the scene actors.

The term was coined by the programmers of MIT's Project MAC. They took the name from Maxwell's demon, an imaginary being from a famous thought experiment that constantly works in the background, sorting molecules.[2] Unix systems inherited this terminology. A derivation from the phrase "Disk And Execution MONitor" is a backronym.[1]

Daemons are also characters in Greek mythology, some of whom handled tasks that the gods could not be bothered with. BSD and some of its derivatives have adopted a daemon as its mascot, although this mascot is actually a cute variation of the demons which appear in Christian artwork.

The jargon file states:

:daemon: /day'mn/ or /dee'mn/ /n./ [from the mythological meaning, later rationalized as the acronym `Disk And Execution MONitor'] A program that is not invoked explicitly, but lies dormant waiting for some condition(s) to occur.

Daemon and {demon} are often used interchangeably, but seem to have distinct connotations. The term `daemon' was introduced to computing by {CTSS} people (who pronounced it /dee'mon/) and used it to refer to what ITS called a {dragon}. Although the meaning and the pronunciation have drifted, we think this glossary reflects current (1996) usage.